The present invention generally relates to a semiconductor processing furnace. More particularly, the invention relates to prevention of liquid spillage from pipes or conduits which convey processing or cooling liquids to semiconductor processing furnaces.
Many processes and applications rely heavily on the use of liquids. Liquids are typically stored in tanks, such as reserving tanks, and are transported from such reserving tanks to process stations where they are required by way of piping lines.
It is desirable in any storage, transportation or process use of fluids for personnel to be aware of any tank or plumbing fluid leaks or breaches. Even minimal fluid leaks can be detrimental, not only from a material loss standpoint, but also from the standpoint of environmental and safety considerations if such fluids happen to be hazardous materials.
A variety of fluid leak detection schemes are known. For example, so-called differential pressure techniques may be used to detect the existence of leaks in a tank or piping. However, such techniques generally fail to identify localization of a leak and may have difficulty if not total inability to detect the existence of very small leaks. Furthermore, such techniques may experience significant time lag between when a leak first occurs and when the leak is detected, rendering such detection techniques undesirable in time-critical leak detection applications.
Piping and tank leaks may also be detected by way of discrete, uninsulated electrode pair placements wherein a fluid leak that causes the fluid to bridge the electrodes is detected as a short across the electrodes or as a significant change in the resistance between the electrodes. The fact that such a technique uses exposed or uninsulated electrodes may be problematic in applications using flammable fluids, as they represent a potential ignition source.
Certain other techniques have been proposed which utilize a coaxial conductor cable wherein the dielectric layer that is intermediate the solid central and braded exterior conductors is porous. Infiltration of the fluid from a leak to be detected into the porous intermediate layer causes a substantial change in the permittivity of the layer at the infiltrated location. Pulse reflection distortion techniques are then utilized to detect the presence and location of the leak. This proves to be a solution requiring expensive and sophisticated electronics for generating and interpreting signals. Furthermore, it is recognized that such techniques may be slow to detect leaks due to wicking effects of the braided outer layer which slows the infiltration of the leaked fluid through the porous intermediate layer and may distribute the liquid over an exceptionally long length of the cable.
Yet another option in fluid leak detection is disclosed in commonly assigned and co-pending U.S. patent application Ser. No. 09/881,389, In that application, a thermal sensing fluid leak detection scheme is described. Temperature changes in the detector due to fluid contact are detected in such a scheme. While the invention described therein is regarded as an improvement over the prior art, it may not meet all requirements of certain fluid leak detection applications. For example, a plurality of such individual thermal leak detection apparatus may be required to adequately canvas an area of interest for the purpose of leak detection. Even then, the granularity of localizing the source of such leaks may be greater than that desired in a particular application.
Therefore, it is one object of the present invention to prevent spillage of a fluid leaked from a conduit.
It is a further object of the present invention to prevent spillage of a fluid leaked from a conduit for at least a sufficient time to facilitate repair or replacement of the conduit.
It is a further object of the present invention to prevent spillage of a fluid leaked from a conduit and immediately detect such leakage of the fluid from the conduit.
It is a still further object of the present invention to prevent spillage of a fluid leaked from a conduit by providing an enclosure on the conduit, which enclosure may further be provided with a sensing element for detecting the leaked fluid and alerting personnel to the need for repair or replacement of the conduit.
In accordance with these and other objects and advantages, the present invention comprises an enclosure, sleeve or tubing which is fitted on a conduit and may be sealed at both ends thereof. In the event of fluid leakage from the conduit, the sealed enclosure, sleeve or tubing prevents spillage of the fluid into the environment of the conduit. A pair of sensor strips electrically connected to a leak detector may be provided between the conduit and the enclosure, sleeve or tubing such that fluid leaked from the conduit and confined by the enclosure, sleeve or tubing causes an electrical short between the sensor strips, whereby the conductivity or capacitance between the sensor strips triggers an alarm signal to the leak detector, which alerts personnel to the need for repairing or replacing the conduit.